Minimum-maximum governor with midrange regulation



United States Patent inventors Jerry A. Clouse Washington; Marvin A.Gates, Chillicothe; John H. Parks, Peoria, lllinois App]. No. 736,306

Filed June 12, 1968 Patented Oct. 6, 1970 Assignee Caterpillar TractorCo.

Peoria, Illinois a corporation of California MINIMUM-MAXIMUM GOVERNORWITH MIDRANGE REGULATION 4 Claims, 2 Drawing Figs.

U.S.Cl 123/140, 123/98, 73/537 int. Cl F02d 1/04 Field 01 Search .173/537; 123/98, 140

[56] References Cited I UNITED STATES PATENTS 2,139,194 12/1938Lichtenstein 123/140 2,159,863 5/1939 Schilling 73/537 2,669,983 2/1954Reddy et al.. 123/140 2,631,025 3/1953 Bone 73/537 2,957,351 10/1960Heinzman 73/537 2,960,327 11/1960 Gaubatz .1 73/537 FOREIGN PATENTS384,976 1/1933 Great Britain 1. 73/517 Primary Examiner-James J. GillAssistant Examiner-Herbert Goldstein Almrney- Fryerffjensvold, Feix,Phillips and Lempio ABSTRACT: A governor which has separate springs forhigh speed and low speed regulation and has a third spring effective atmidrange engine speeds to prevent sudden acceleration of the engine,which is undesirable and may occur, for exampl when the engine isoperated under light load.

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JOHN H.- PARKS ag i r -w TTORNEYS I NARVIN'RGR MlNlMUM-MAXTMUM GOVERNORWITH MIDRANGE REGULATION The present invention was designed for use oncompression ignition engines used in trucks where a foot acceleratorpedal is generally employed for adjusting the engine governor, but it isalso applicable to engines in other types of service. Considering thetruck application, for example, there are occasions when increasedengine speed demanded is opposed by a heavy load and acceleration isgradual. In the absence ofload or where the load is very light,acceleration may take place so suddenly as temporarily to interfere withthe operator's control and create an awkward and sometimes dangeroussituation.

The present invention provides means in the form of a third governorspring which is effective after the minimum range spring controlling lowspeeds has obtained full compression. It is at this time that undulyrapid acceleration often occurs. The third spring of the presentinvention then becomes operative, providing high regulation governing,to prevent such acceleration.

The invention is described in detail in the following description byreference to the accompanying drawing and objects and advantages of theinvention will become apparent as the description proceeds.

In the drawing:

FIG. 1 is a central vertical section through a governor embodying thepresent invention; and

FIG. 2 is a perspective view which shows a spring which is employed formidrange regulation.

The governor shown is contained in the housing secured to one end of afuel pump housing, a portion of which is shown at 12. Conventionalflyweights 14 are pivoted, as at 15, to a rotatable carrier 16. Gearteeth 17 are formed on one of the carriers and mesh with the gear 18which is engine driven in this case by a camshaft, a portion of which isshown at 19 in the pump housing. Outward movement of the flyweightscaused by engine speed and inward movement which results from varyingthe force of the governor springs, results in adjustment of a fuel feedrack in the pump housing shown at 20 and this rack imparts angularadjustment through a gear 21 to a plunger 22 of one of the severalengine fuel pumps, all in a conventional manner. The transmission ofmotion from the flyweights to the fuel rack 20 is accomplished by adouble acting hydraulic servomechanism generally indicated at 24 andexplained in detail in Parks & Wellwood Pat. No. 3,145,624. It willsuffice for an understanding of the present invention to know that thegovernor flyweights move and are adjusted by a reaction member 26 on avalve spool 27 which controls flow of fluid under pressure through apassage 28 to and from a chamber 29 which is effective through a piston30 to adjust the fuel rack. In the present governor a control lever 32actuated through suitable linkage from an accelerator pedal (not shown)may be moved in a counterclockwise direction and has a bifurcated endbearing against the end of a collar 34 to move it toward the right, asviewed in the drawing, for com pressing the springs of the governorspring assembly. It is slidable on a bearing 36 which is pressed into asuitable bore in the end of the housing 10. The spring assembly is shownas in shutdown condition and upon starting of the engine at low idle orslightly greater speed setting, the flyweights will swing outwardly andurge the reaction member 26 against a seat 38 of a low speed spring 40seating at its opposite end against the seat 42 of the heavier highspeed range spring 44. This spring has a seat 46 at its opposite endslidable on a sleeve 48'and has an assembled preload. The sleeve 46 alsoacts as a seat for a midrange governor spring 50 which has an oppositeseat formed on the collar 34. One form which the midrange spring 50 mayassume is that ofa finger spring such as that illustrated in H6. 2,though other springs having a. comparable rate and 5 force may of coursebe used. As the engine is started, the low speed range spring 40 will beslightly compressed so that the engine will start at or above a low idleposition. To increase the speed toward the top of the minimum governedrange, the

accelerator is actuated to swing lever 32 counterclockwise with nodeflection of the high speed spring due to its preload and only slightdeflection of the stiff midrange spring so that motion will betransmitted through collar 34, spring seat 46 and sleeve 48 to compressspring 40. As the maximum speed under the low speed range spring isapproached, the end of the sleeve abuts spring seat 38 so that thespring is no longer functioning. If at this point furthercounterclockwise motion is imparted to lever 32 it would normally movethe rack directly and result in rapid acceleration until the: enginespeed reached a point where the tlyweight force equalled the high speedpreload force at which time normal governing would occur. The midrangespring 50 prevents this acceleration. lt is not preloaded and will becompressed, acting through preloaded spring 44 and now ineffectivespring assembly 40 and will be effective with the flyweights 14 togovern engine speed in the midrange. Further movement of lever 32demanding greater engine speed will compress spring 50 to the pointwhere its stiffness equals that of the preloaded high speed range spring44 and the two will act together in opposition of outward movement ofthe flyweights in the conventional manner.

We claim:

1. In a fuel feed rack actuator for a compression ignition engine, agovernor comprising separate spring means for regulating the speed ofthe engine at low, intermediate and high speeds, respectively, first,second and third serially arranged spring means, said spring meansadapted to be operatively connected to a fuel feed rack to regulatemovement of said fuel feed rack and adapted to urge said fuel feed rackin a first direction, speed responsive means connected to said seriallyarranged springs to urge them in a second direction in opposition tomovement in said first direction, said first spring means having apredetermined low spring rate to regulate movement of said fuel feedrack at predetermined low speeds to prevent excessive acceleration ofsaid engine at said low speeds, said third spring means having apredetermined intermediate spring rate to regulate movement of said fuelfeed rack at said predetermined low speeds and at predeterminedintermediate speeds to prevent excessive acceleration of said engine atsaid low speeds and said intermediate speeds, said first spring meansineffective to regulate movement of said fuel feed rack at speeds abovesaid predetermined low speeds, and said second spring means having apredetermined high spring rate to regulate movement of said fuel feedrack at predetermined high speeds to prevent excessive acceleration ofsaid engine at said high speeds, said third spring means effective withsaid second spring means to regulate movement of said fuel feed rack atsaid predetermined high speeds.

2. A governor as in claim 1 wherein said third spring comprises a fingerspring having variable rate.

3. A governor as in claim 2 wherein said third spring cooperates withsaid first spring to cause a smooth transition from the low speed to theintermediate speed.

4. A governor as in claim 1 wherein said first and second spring meanscomprise coil springs and said third spring means comprises a fingerspring and said second spring is assembled in the governor under apredetermined preload.

